How about working your way to I-81 to I-78 to I-287 over the Tappan-Zee toll bridge. As mentioned you have a couple of choices at this point. You can continue east on 287 to I-95 north to I-195 in Providence RI and on to Cape Cod. Or after the Tappan-Zee you could work your way to I-84, which features on going road construction in Waterbury CT.,then on to the Ma. Turnpike (toll road) at Surbridge then I-495 to the Cape. Be sure NOT, NOT to hit the Bourne or Sagamore bridges after 1 or 2 pm on any Friday afternoon. If you do expect 2 to 4 hours minimum delays. Those are the only 2 bridges to the Cape and they only have 2 lanes each so it's slow going.